1. Field of the Invention
This invention relates to a fabric-softening detergent composition containing surfactant, builders and a fabric-softening layer silicate of the smectite type with an incrustation-inhibiting synthetic layer silicate.
In many cases, a soft, full feel is to be imparted to washed fabrics. One way of improving the wearing comfort of fabrics is to treat the washed fabrics with fabric-softening agents in the final rinse after washing. For this purpose, cationic compounds are generally allowed to act on the washed fabrics so that the fabrics, having taken up the cationic compounds, feel soft after drying. Another way of obtaining this effect is to allow the fabric-softening agents to act on the fabrics during the subsequent drying of the washing in an automatic dryer. One feature common to both methods of softening fabrics is that the softening agents have to be allowed to act on the fabrics separately from the detergent after the actual washing process. This involves additional effort which could be avoided if the softening agents could be allowed to act on the fabrics at the same time as the detergent, i.e., during the washing process. However, high-performance detergents generally contain anionic surfactants which are incompatible with the cationic fabric softeners because they react with them to form compounds which are substantially ineffective in regard to their detergency and their softening effect.
2. Discussion of Related Art
Attempts have been made to overcome the afore-mentioned problem by employing nonionic fabric softeners. However, nonionic compounds have the disadvantage compared with cationic fabric softeners that, unlike the cationic compounds, they are not substantially or completely adsorbed by the textile fibers. Accordingly, it has been proposed in U.S. Pat. Nos. 3,966,629 and 4,062,647 to use clay-like minerals of the smectite type which are compatible with anionic surfactants as fabric-softening agents. The clay-like materials mentioned are adsorbed onto the fibers of the fabrics and, by virtue of their layer-like crystal structure, exert a softening effect when used during the actual fabric washing process. Thus, layer silicates of the type in question have been used for some time in fabric-softening detergents. One disadvantage of these softening layer silicates is that they accumulate on the fabrics and, hence, can contribute towards additional incrustation of the washed fabrics under certain conditions.